Pulse oximetry is a procedure used to measure the oxygen level (or oxygen saturation) in the blood. It is considered to be a noninvasive, painless, general indicator of oxygen delivery to the peripheral tissues (such as the finger, earlobe, or nose).ulse oximetry is a procedure used to measure the oxygen level (or oxygen saturation) in the blood. It is considered to be a noninvasive, painless, general indicator of oxygen delivery to the peripheral tissues (such as the finger, earlobe, or nose).
The area of the World Ocean is about 361.9 million square kilometers (139.7 million square miles), which covers about 70.9% of Earth's surface, and its volume is approximately 1.335 billion cubic kilometers (320.3 million cubic miles).
Percentage of Landmass. Most of the world's surface is covered in water, in the form of oceans. The remaining landmass of Earth amounts to approximately 29 percent of the surface. Of this remaining 29 percent, deserts of all types constitute an estimated 33 percent, or one-third, of the Earth's total landmass. This large percentage is due in part to the vastness of the world's largest desert -- Antarctica.